Emails get misplaced and you might find that you are out of luck when you need to find a past serial number.
The best place to find all of your serial numbers would be to log into your Spitfire account and then look here:
https://www.spitfireaudio.com/my-account/serial-numbers/
This page also allows you access to your order history which may be useful for your records.
If you find that the serial number you are looking for is not there, please contact us HERE with all of the relevant information.